1. Field of the Invention
The present invention pertains to aeronautics and, more particularly, pertains to the field of parachute canopy construction.
2. Description of the Related Art
Prior art ram air parachutes have a canopy formed by spaced upper and lower fabric panels connected interiorly of the canopy by a plurality of spanwise spaced ribs which are secured to the panels and which are flexible fabric panels having the shape of an airfoil cross section. The region between the upper and lower panels is forwardly open for admission therebetween of ram air pressure which is generated by forward motion of the parachute and which inflates the canopy into an airfoil constrained by the ribs to have a cross section conforming to the shape of the ribs. In prior art ram air parachutes, suspension lines depending from the canopy are secured to the lower panel at points spaced along the ribs so that suspension and other loads are tranfferred between the upper and lower panels by the ribs. The ribs divide the inflated canopy into cells spaced spanwise of the airfoil, and the ribs may have a construction providing for limited spanwise air flow through the panels between the cells to promote inflation of all the cells when, as during parachute opening or operation in a crosswind, airflow is not directly into the forward opening of the canopy. Typical constructions for this purpose include openings cut through the ribs, openings left between reinforcing tapes incorporated in the ribs, or the use of mesh fabric for the ribs.
However, in all these constructions spanwise air flow between the cells is substantially impeded by the ribs so that parachute opening may be undesirably slow for some purposes and so that the spanwise end cells often deflate during parachute maneuvers or do not fully inflate on opening. These problems, although dangerous, are usually correctable by a fully functioning parachutist, but can be uncorrectable with other loads. In any event, the ribs contribute substantially to the weight of a ram air parachute and greatly increase the volume of the parachute when packed.